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(-Model.) 3 Sheets-Sheet 1.

J. M. POLLARD.

SPLIT PULL'EY. v No. 01, 86 P tentedA 1-. 16, 1889.

u. PETERS. Pholo-Li1hognphen Washington. v.0.

(ModeL) 3' Sheets--Sheet 2.

J. M. POLLARD.

SPLIT PULLEY.

No. 401,586. Patented Apr. 16, 1889..

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(ModeL) 3 SheetSheet :3.

J. M. POLLARD.

SPLIT PULLEY.

Patented Apr. 16, 1889.

N. PETERS. Phulo-Lkhogrdphur, Wishingmn, D. C

UNITED STATES PATENT JAMES M. POLLARD, OF \VASHINGTON, DISTRICT OFCOLUMBIA.

SPLIT PU LLEY.

SPECIFICATION forming part of Letters Patent No. 401,586, dated April16, 1889. Application filed June 30, 1888. Serial No. 278,630. (Modell)T allwhom it may concern.-

Be it known that I, JAMES M. POLLARD, of Washington, District ofColumbia, have in vented anew and useful SplitPulley, of which thefollowing is a specification.

My invention is especially designed for small pulleys, though applicableto any diameter, and is an improvement in the mode of fastening theparts together and to the shaft with which or upon which it is torotate.

Split pulleys have become almost indis- V pensable, because of theirready application to shafting already in place without the necessity oftaking down the shaft and removing other pulleys, 850., as in the caseof solid pulleys; but it has heretofore been found impracticable to makea split pulley of less than twelve (12) inches diameter, because of thelack of room for the fastening-bolts, &c. A few split pulleys have beenmade of nine (9) and ten (10) inches diameter, but at great expense andinconvenience, and these pulleys were lacking in strength, because therims were necessarily Very thin to admit of room for the fastening boltsand nuts with which the parts are clamped or drawn together.

The objects of my invention are to dispense entirely with the latter; toconstruct a split pulley of any desired size down to the smallest used,even if but two or three inches in diameter; to dispense entirely withmetal in any form when making wood pulleys, and to so construct theparts that they will firmly interlock with each other, and while bindingthe rim securely together will. also frictionally clamp the hub upon theshaft with the requisite degree of force to dispense with spline or keyor set-screw or other fastening device.

A further object of my invention is to produce a pulley of the greatestpossible strength, simplicity of construction, ease of manufacture andapplication, and least possible number of parts.

I attain these objects by the mechanism illustrated in the accompanyingdrawings, in which- Figure l is an end view of a pulley constructedaccording to one of the best forms of my invention; Fig. 2, a side View,partly in section, on the dotted line X X of Fig. 1; Fig. 8, an end viewof a pulley, showing a modification; and Fig. 4s, a plan of the upperhalf and elevation of the lower half of the bushing for same; Fig. 5, anend View of another modification; and Fig. 6,'a side View of same,partly in section, on the dotted line Y 7; Fig. 11, a side View of thebushing and shaft of pulley shown in Figs. 7 and 10, the bushing beingshown applied to the shaft and in vertical section lengthwise of thelatter. Fig. 12 is an. end view of a very small wood pul ley with ironbushing. In each of the end views I have shown in dotted lines thethickness of bushing and rim at the other end of the pulley, thusindicating the wedge or incline of the parts; and Fig. 13, a similarview of one of my split pulleys, in which the rim is made to bind uponthe shaft.

It will be seen that my pulley consists, essentially, of four parts- W2,of two duplicate portions constituting the hub or bushing and of twoduplicate portions constituting the riIn -and that the construction issuch that when the bushing, as in Fig. 11,. is drawn endwise into therim shown in Fig. 10 the wedge form of the parts binds the bushingtightly together, or closes the two halves toward each other and uponthe shaft. At the same time the two halves of the rim are also drawnforcibly together by the transverse dovetail inclines of the bushing, sothat the parts are held together and to the shaft with a force orfriction-grip exactly proportioned to the force used in driving theparts together, all of which will nowbe specifically described.

A A in the drawings are the two halves of the rim, and these, as beforestated, are exact duplicates of each other, so that a description of onewill suffice.

As shown in Fig. 3, the rim is grooved or channeled out to any requisitedepth, the

vertical face of this groove are being parallel I00 to the axis of shaft0 and of equal depth from end to end'of the pulleythat is to say, ofequal depth at all points from the vertical central dividing-plane ofthe pulley-rim. The upper and lower portions of this mortise or channelare, however, tapered from end to end in two planes, as shown in thedotted lines, which indicate the dimensions of both mortise and bushingat the other end of the pulley.

The bushing B in Fig. 4 shows in plan the inclines a a, which serve bytheir wedge form to draw the two halves of the pulley together, and inelevation the incline b or wedge by means of which the rim forces ordraws together the two halves of the bushing. This form would beinconvenient to manufacture, and is shown and described merely becauseit illustrates better than any other form the double wedge action of thedevice. The curved or hollowed incline shown in Figs. 1, 2, 7, 10, and11. and the dovetail incline shown in Figs. 5, 6, 8, and 9 are exactequivalents in their mode of action. The two parts of the bushing areeither cut apart with a thick saw after having been bored out for theshaft as a Whole or are separated a short distance when being bored; orwhen made separately, as I design, the bore in each half is less thanthe half of a circle, so that when applied to a shaft the bushingscannot come in contact with each other, and the entire wedge action issustained by the shaft. It will be seen that a machine need only bedesigned to make half-bushings and half-rims I prefer in practice toconstruct small pulleys as shown in Figs. 7, 10, and 11, and largersizes, or those above one foot in diameter, somewhat as shown in Fig. 9.By the firstnamed plan the rim is left of greater thickness at thepoints a a Figs. 5 and ,7, and the bushings are more readilyinterchangeable. The rim is built up solidly of layers of wood glued andpressed together, with the grain of alternate layers crossing each otherat a right angle, and to a thickness to form the requisite width of faceor length of pulley. It is then out or split into two equal halves orparts and dadoed out for the bushing. The latter is bored to therequisite size for the shaft and shaped exteriorly like the mortise inthe rim when the two parts are placed together. The fit between thesides of the bushing and the sides a a of the mortise in the rim is notso close as to bind with any force even when the parts are forciblydriven together, while the bushing is upon its wedgesurfaces slightlywider vertically than the mortise, so that it cannot be driven in flushwith the end of the pulley. The grain of the wood in the bushing istransverse to the shaft and at right angles with the division line orplane of the rim-sections, as shown by the lines in Fig. 1. It will thusbe seen that the tensile strength of the wood in the bushing isavailable for holding the rim against centrifugal action and forrotating the shaft or pulley, as the case may be that the tensilestrength of half the layers of the rim is exerted to pull therim-sections together, and that the tensile strength of the remainingrim-sections is exerted in drawing the bushings together upon the shaft.In practice I have found it best to place the bushings in position uponthe shaft and to drive the rimsections upon them by striking the halvesalternately with a mallet. There is no danger of splitting the rim andno difficulty in securing a grip upon the shaft that is amply suflicientto perform any possible amount of work without slipping. Instead ofdriving the parts together, they may be drawn and secured by bolts andnuts passing from the thick end of the bushing on a line parallel at allpoints to the axis of the shaft and engaging the opposite ends of thepulley-rim, or by any other suitable means; but I have found thisunnecessary in practice, and so do not illustrate or claim such means.It is designed to make the bushing externally of but two or three sizesfor all small pulleys-for instance, a standard size and taper forpulleys five, six, seven, and eight inches in diameter, and another forpulleys nine, ten, eleven, and twelve inches diameter. For smallerdiameters, special plans will be made. By this means the bushing willbeinterchangeable, and may be boxed and kept in stock to fit. variousdiameters of shafting.

When pulleys of great width of face are required, they may be made totaper from each side to the center and the bushing of standard sizesdriven from each end, two sets of bushings being used for each rim insuch case.

While I have described a wood pulley, I do not at all limit myself tothe use of this or any other material. For specially small pulleys wherea comparatively large bore is required, an iron bush ng may be used, asshown in Fig. 12.

Instead of making the mortises in the rim and the exterior of thebushings incline or taper lengthwise of the pulley, these parts maymerely be dovetailed and tightened upon the shaft by means of dowel-pinsor wedges or bolts, as indicated at K of Fig. 12; but these methodswould be inferior to the methods I have adopted for practice, and areentirely within the intent of my invention.

Many other modifications of form might be devised that would accomplishthe same results and be entirely within the spirit and scope of myinvention, and I have not attempted to show or even to devise them. Ialso intend'to make loose pulleys as shown in Fig. 12, and to do this byrabbeting the iron bushing and using space blocks b 1) between the edgesof the two parts of the bushing, so that the pressure derived from thewedge action of the parts shall be borne by the bushings coming incontact with each other and not upon the shaft. These space-blocks canthen from time to time be reduced in thickness and the bushings broughtcloser together, thus compensating for wear.

In my pulley, as shown in Fig. 13, instead of having the bushing aloneengaging the shaft, I draw the sides of the pulley-rim against theshaft, so as to bind thereon. This pulley I make with the shaft-openingof a diameter from a to a less than the diameter of the shaft by thethickness of the said out by which the pulley is split.

The bushings B B, which draw the pulleyhalves together, are to be shapedsubstantially like those shown and described hereinbefore, but arenarrower, so as'to engage with their inner sides only small portions ofthe periphery of the shaft. Space is thus left for the inner sides ofthe two pulley halves to engage and bind upon the shaft.

In full lines in Fig. 13 the sides of the narrow bushings B B are shownas substantially parallel with each other. If desired, I contemplate,however, making them as shown in dotted lines in said figure, with theirsides, as seen in end View, sloping from their outer portions away fromeach other.

My invention can obviously be applied to the fastening of a wooden ormetallic rim upon a pulley or wheel, as well as to the placing of apulley on a shaft. In such case the rim, being in two halves andprovided with any one of the described forms of bushing ways or grooves,is fastened or bound upon the exterior of the pulley or wheel by thebushings corresponding in shape with the ways in the rim.

My split pulley is also capable of use as a shaft-coupler. As indicatedin dotted lines in Fig. 6, it can be so placed as to bind at the sametime upon the contiguous ends of two shafts in line with each other.

Having thus described my invention, I claim- 1. In a split pulley, thetwo-part rim and two-part bushing provided with interlocking ribs andgrooves adapted to draw and lock the half-rims together as they areforced endwise upon the bushing, substantially as and for the purposespecified.

2. A split or separable pulley consisting of two duplicate portionsconstituting the rim and two duplicate portions constituting the hub orbushing, and having inclined or wedge surfaces whereby it is made selffastening and tightening by the act of forcing the parts together, asset forth.

3. A split or separable pulley having interior doubly-inclined mortises,and a separable bushing having exterior doubly-inclined surfaces andbored to fit over or upon a shaft, as set forth.

4. In a split or separable pulley, the twopart rim and the woodenbushing adapted to hold the rim parts together, having the grain of itswood at right angles to the Shaft/013611- ing in the bushing and to theplane of division of the rim into its two parts, substantially as andfor the purpose shown.

5. In a split or separable pulley, the twopart bushing with each parthaving a doublyinclined wedge shape, being tapered uniformly from end toend, and having on its inner side a longitudinal groove to partiallyinclose a shaft, and on its outer side being grooved, dovetailed, orchanneled longitudinally, in combination with the two half-rims havingtheir inner sides shaped to fit the bushing, so that as the rim andbushing are moved longitudinally with reference to each other the partsof the rim will be drawn together and the parts of the bushing will beforced toward each other, substantially as and for the purposespecified.

6. In a two-part split pulley, the two parts of the rim each having adovetailed or equivalent undercut mortise, in combination with atwo-part split bushing shaped exteriorly to fit said mortise,substantially as set forth and described.

7. In a two-part split pulley having a dovetailed or equivalent undercutwedge-shaped mortise in each part, a two-part split bushing shapedexterior-1y to fit said mortise and bored to fit over or upon a shaft,the construction being such that when the bushing and other parts of thepulley are being put together the bushing draws and holds the two partsof the rim forcibly together and the rim draws and holds the two partsof the bushing firmly upon the shaft, as shown and described.

8. In a split or separable pulley, in combination with the two halves ofthe pulley-rim, formed of layers of wood glued and pressed together, thegrain of the alternate layers crossing each other and having undercutwedge-shaped mortises in each half, a separable bushing formed of woodand having the longitudinal fibers or grain crossing the bore at a rightangle thereto, whereby the tensile strength of the wood of the bushingis available for drawing the two parts of the rim together or towardeach other, and the tensile strength of a part of the wood composing therim is available for drawing the two parts of the bushing toward eachother, as shown and described.

9. A split or separable pulley made in two equal or like halves unitedand held together solely by a split or separable bushing.

10. A split or separable bushing made in two equal and like halves, incombination with a rim, also made in two equal. and like halves, thebushing forming the sole connection between the two halves of the rim,and the rim forming the sole connection between the two parts of thebushing, as set forth.

11. In a split pulley, in combination with the tapering bushing dividedlongitudinally into two parts, each part provided on its outer side witha longitudinal groove or channel diminishing in Width toward the smallerend ing, substantially as and for the purpose of the bushing, thepulley-rim divided into described.

tWo parts on a longitudinal plane at right angles to the plane ofdivision of the bushing,

each part rim being provided on its inner Witnesses:

side with ribs to engage the opposite sides of E. L. MILBURN, thegrooves in the outer sides of the bush- CHAS. P. WIGGINS.

J. M. POLLARD.

It is hereby certified that in Letters Patent No. 401,586, granted April16, 1889, upon the application of James M. Pollard, of WVashington, D.0., for an improvement in Split Pulleys, an error appears in the printedspecification requiring correction, as follows: In line 1, page 4, theWord smaller should read larger,- and that the Letters Patent should beread with this correction therein that the same may conform to therecord of the case in the Patent Office.

Signed, conntersignecl, and sealed this 23d day of April, A. D. 1889.

CYRUS BUSSEY, Assistant Secretary of the Interior.

[SEAL] Oountersigned:

O. E. MITCHELL,

Commissioner of Patents.

